BACKGROUND: Newborns depend on the transfer of IgG across the placenta to acquire protection against pathogens. We assessed the placental transfer of SARS-CoV-2 antibodies, primarily derived from infection, from seropositive pregnant women enrolled in a pregnancy cohort in Kilifi, Kenya. METHODS: The study was nested within a prospective observational multi-country cohort study. All available paired maternal delivery and cord blood samples were selected. Maternal sera were tested for SARS-CoV-2 receptor binding domain (RBD) IgM/IgG total antibodies using the Wantai assay. For positive samples, maternal and corresponding cord blood samples were tested for SARS-CoV-2 IgG antibodies against the spike (anti-spike) and nucleocapsid proteins (anti-NCP) using ELISA kits from Euroimmun. RESULTS: A total of 492 (56.1%) out of 877 maternal delivery samples were positive for RBD IgM/IgG total antibodies. Of these, 416 (84.6%) were seropositive for either anti-NCP IgG, anti-spike IgG antibodies or both. A total of 412 out of 496 (83%) cord blood samples tested positive for either anti-NCP or anti-spike antibodies. The geometric mean ratio was 1.04 (95% CI: 0.90, 1.21), indicating no significant difference between the anti-spike IgG concentration in cord and maternal blood samples. The log-transformed maternal and cord blood anti-spike IgG concentrations showed a weak positive correlation (r = 0.364, n = 496, p
BMC Infect Dis
01/07/2025
25
COVID-19, Efficiency, Placental transfer, SARS-CoV-2 antibodies, Seropositivity, Humans, Female, Pregnancy, Antibodies, Viral, Prospective Studies, SARS-CoV-2, COVID-19, Immunoglobulin G, Infant, Newborn, Adult, Spike Glycoprotein, Coronavirus, Immunoglobulin M, Fetal Blood, Placenta, Pregnancy Complications, Infectious, Immunity, Maternally-Acquired, Kenya, Young Adult, Coronavirus Nucleocapsid Proteins, Maternal-Fetal Exchange